DEF on E with countdown

[GrizEagle]

I had a similar issue earlier this year. I think the problem is actually overfilling the DEF tank. I filled it but the pump (truck stop) was problematic and I thought it wasn't filling it all the way. It took my truck over 300 miles for the gauge to finally rise. Ironically, I was driving to the dealer to get the service department to diagnose the issue...

I fill my DEF at truck stations but after I had this issue I stop at the first click/shut off of the nozzle. Haven't had a repeat issue since then. I saw another post on a different forum with someone having the same experience.

 

[Brutal_HO]

I don't know if there's a similar TSB for the DT, but there is one for the HD trucks. For 2019 they switched from an RF to a UF sensor. No manual float.

The root cause is overfill and not having an air gap that is needed for the sensor system to work properly.

You might ask the dealer to check for a similar TSB.

It's good to review the linked TSB for info on the proper method to clear this while driving, which is stable, not bumpy, straight highway miles.

DEF OVEFILL OR ICE

NUMBER: 18-034-21

https://static.nhtsa.gov/odi/tsbs/2021/MC-10194039-9999.pdf

 

[gorilla57]

This problem IS from overfilling the tank. I filled mine all the way up to the top with a 2.5gal jug and I actually had a CEL pop up, the P203E code. On the way to the dealership, the gauge started working, but the CEL was already on. So, in a way, I did the P203E DEF gauge reset drive cycle without even knowing it. The mechanic knew instantly what the code was gonna say when I told him that I filled the DEF tank up. He reset it and I've never had the problem again. Never had this issue with my 2015 Ram 3500 because it was the RF style sensor.

 

[dsw1000]

Interesting. The tank is definitely full to the brim. I had 100 miles left on the countdown when I got to the dealer this morning. About halfway to the dealer the CEL came on. I'll see what they say the code was and ask about the TSB.

 

[dsw1000]

The issue was confirmed to be overfilled def tank with the p203 code. They drained 2 gal and told me not to fill with more than 4 gallons total.

 

[NorthStar]

The issue was confirmed to be overfilled def tank with the p203 code. They drained 2 gal and told me not to fill with more than 4 gallons total.

Good to know. Translation of p203 means one needs to drain out some DEF to correct the issue…assuming the CEL resets after a certain number of cycles, it is a very easy process.

A siphon hose, container, and unhook the tube on the top back side of the DEF tank to siphon out any excess will get one back in business. Then dilute the DEF down and spread it over your lawn to watch it green up in a few days.

 

[Hasti17]

You wanna laugh? I have a canyon Duramax And when my DEF gets low, you literally cannot just grab a gallon of def and top it off....
If the tank is not refilled completely once the "countdown" starts. Then it will continue uninterrupted. Asked a dealer and other GM diesel owners and what i wastold is that it was a feature, not a bug. Almost got stranded an hour from home getting to work one day, i stopped myself JUST before turning off the truck and went to a walmart to buy enough to fill it.

Only when i started looking at other brands diesels did people look at me funny when i mentioned it

 

[palumaa]

I also have a problem with the DEF tank on my RAM 1500 2022. I filled the tank completely, but the gauge still shows that it is empty and I get the error messages.

 

[GrizEagle]

I also have a problem with the DEF tank on my RAM 1500 2022. I filled the tank completely, but the gauge still shows that it is empty and I get the error messages.

Sometimes if you fill it completely, it is then "over full" and the sensor cannot detect the level. I have had that happen to me in the past. Usually if you drive it enough, you will use some of the DEF and then it will detect the level. Otherwise, if you are close on the countdown, you may need to drain some out of the tank.

 

[Malodave]

I try to add a Jug when the Gauge reads 1/2 tank. Occasionally I will run it down to 200 miles left and add 2 Jugs.
That way I know most of the older DEF Fluid is changed out. I once had it at 40 miles left.

Malodave

 

[palumaa]

Sometimes if you fill it completely, it is then "over full" and the sensor cannot detect the level. I have had that happen to me in the past. Usually if you drive it enough, you will use some of the DEF and then it will detect the level. Otherwise, if you are close on the countdown, you may need to drain some out of the tank.

Thanks. It shows 360 miles left on the dashboard, has been driven almost 400 miles and still shows the exact same message.

 

[Wtray]

I try to add a Jug when the Gauge reads 1/2 tank. Occasionally I will run it down to 200 miles left and add 2 Jugs.
That way I know most of the older DEF Fluid is changed out. I once had it at 40 miles left.

Malodave

This is what I do. buy a jug from Costco when my truck approaches half a tank. Pour it in and good to go for a couple months.

 

[66Fuelie]

Today on my 23 I got 305 miles until engine shutdown with the def gauge showing 1/4 tank left. The notice kept coming up about every 5 min.
I drove 40 miles and it still said 305 miles till shutdown
I normally just put in one jug and it bumps it up to 3/4 tank.
Tom